SSLV1.1 builds & fairy tales

[Salas]

Heat sinks I am using are Aavid Thermalloy 8C/W P/N 531302B02500G

Tiny in any case. How hot is the sink itself?

 

[Salas]

Here's a picture

Mount the Mosfet higher on top mounting hole. Half its back ain't touching it seems. That can explain it if I see well.

 

[mjock3]

I is hot. How much larger sink do I need? Sorry I thought they were ok.

 

[mjock3]

Mount the Mosfet higher on top mounting hole. Half its back ain't touching it seems. That can explain it if I see well.

OK I will try that. Later tonight. Thank you.

 

[Salas]

I is hot. How much larger sink do I need? Sorry I thought they were ok.

You could do OK if something like 60-65C can be measured on them after CCS setting for the purpose, dummy, and mounting are good. I generally prefer no more than 50-55C for long term, heatwave periods etc. but ~150F on sink itself is decently reliable for such semis.

 

[mjock3]

Salas,

I also bought some heatsinks that are 5C/W, would that help?

 

[Salas]

How much voltage there is across the blue 2.5R ?

 

[mjock3]

It was 2.45 volts.

 

[Salas]

Salas,

I also bought some heatsinks that are 5C/W, would that help?

If they mount better use them. Contact quality between semi's full back and sink is of main importance, think about the lengths overclocking PC users go for CPU compounds, optimal spread, you get the importance, same stuff but more tolerable here.

 

[Salas]

It was 2.45 volts.

0.98A if it is 2.5R spot on, so no mistake there. Should be the mounting back gap. Solve that first. Was the dummy hot also? I wanna know that current flows to dummy for sure too.

 

[mjock3]

I have replaced the heatsink with the other one full contact on back. It still gets very hot. I unplugged it after it hit 240 F. Dummy load does get warm. The transformer I am using is a Triad vps16-2700. Could that cause this?

 

[Salas]

Do you connect F+,S+ at one dummy's lead and F0,S0 at the other?

 

[mjock3]

Do you connect F+,S+ at one dummy's lead and F0,S0 at the other?

Yes

 

[Salas]

Is IR9610 CCS Mosfet as hot? And what is the AC voltage on PCB's trafo connector while working?

 

[mjock3]

Is IR9610 CCS Mosfet as hot? And what is the AC voltage on PCB's trafo connector while working?

Salas,

I am sorry it is the IR9610 that is hot, the 9530 is about 109 F. AC voltage at connector is 18.35 V.

 

[Salas]

Now we are talking. ~19W dissipation on it. Use half a secondary VAC.

 

[Salas]

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[Salas]

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[mjock3]

Thanks Salas for all the help.

 

[acidbrain]

My shunts drive a (Salas)MC-pre, I changed the Vref from 2 to 3 red leds and lowered the R from about 900 to 380 Ohm. Most be subjective but I've got the feeling that the music is a bit faster and I'm hearing more fading instruments.

-Now for the 30V MM stage I want to use a combination of 3 LM329(6.9V) /4 leds / R about 220 Ohm

Salas, is the LM 329 the best choice or do you have another favourite ?